Chiang Mai Journal of Science

Segmented triblock terpolymers of L-lactide, e-caprolactone and glycolide have the ability to biodegrade by simple hydrolysis in the human body. They therefore have the potential for use in biomedical applications such as absorbable surgical sutures. The particular terpolymer studied in this research work had an overall composition of L-lactide : e-caprolactone : glycolide = 70 : 25 : 5 mol %. Monofilament fibres of the terpolymer were produced by melt spinning using a small-scale fibre extrusion apparatus. Under the processing conditions used, which involved rapid cooling, the as-spun fibres were obtained in an almost completely “quenched amorphous” state. Subsequent off-line hot-drawing and annealing steps were then employed in order to induce crystallization and to build into the fibre the required degree of molecular orientation necessary to develop its mechanical properties. The dependence of these mechanical (tensile) properties on the processing conditions used was also studied, while X-ray diffraction (XRD) was used to determine molecular orientation and crystal structure. It was found that the crystal structure in the fibre after hot-drawing and annealing was predominantly that of the a-form of poly (L-lactide) and that it was this part of the matrix which was responsible for the fibre’s tensile strength.